Korean oak wilt (KOW) caused by Raffaelea quercus-mongolicae and its vector, Platypus koryoensis is one of the most severe forest pests in Korea. In spite of its importance, information about dispersal of P. koryeonsis is very limited. In here, a hypothesis related to long distance dispersal (LDD) of KOW reflecting behavior of P. koryoensis is proposed. When attack density of P. koryoensis increased, location of entry holes in the trunk moved to upward. The individuals which escaped from entry holes in upper trunk had potential to fly upper part of trees and they flew longer distance probably by aid of winds. We suggested that this density dependent dispersal of the beetle explain the spatial dynamics of KOW in large scale.

Korean Oak Wilt (KOW), was first recorded in Gyeonggi Province in 2004, and since then has increased steadily in its occurrence and ecological and economic impacts. Platypus koryoensis vectors the symbiotic fungus Raffaelea quercus-mongolicae, which is the causative agent of KOW. KOW may be closely related to recent climate changes, which have allowed P. koryoensis to extend its distribution range in Korea. And it results in greater overlap with the susceptible host tree, Quercus mongolica throughout Korea. In this regard, changes in the climate suitability of P. koryoensis and Q. mongolica were predicted using CLIMEX model and the influences of other environmental factors such as elevation and the number of days with heat wave were also identified in this study.

Spatio-temporal distribution pattern of an ambrosia beetle, Platypus koryoensis (Murayama) which is vector of Raffaeleaquerci-mongolicae K.H. Kim et al, a causative agent for Korean oak wilt (KOW) was examined in the stand level. Spatial distribution of P. koryoensiswas influenced by their density. Relationship between degree of aggregation and density was positively correlated when the density was extremely low or high whereas the relationship was reverse when the density was intermediate. Patch of P. koryoensis formed around or near dead trees or partial dead trees, suggesting these trees indicated epicenter of P. koryoensis. Fraction of trees attacked by less than 100 individual of P. koryoensis in the stand per year increased abruptly whereas fraction of trees attacked over 1,000 individuals of P. koryoensis increased gradually. Our results showed that the dead trees would be an epicenter of P. koryoensis and the number of trees killed by the ambrosia beetle would be reduced by lowering total population of the ambrosia beetle around the epicenter.